Multiple fuse



March 17, 1936. s. J. WYNN 2,034,366

MULTIPLE FUSE Filed July 21, 1933 INVENTOR- SH'MUEBLY Jbsem \MYNN ATTO mPatented Mar. 17, 1936 UNITED "STATES PATENT OFFICE 14 Claims.

This invention relates to new and useful improvements in a multiplefuse.

It is an object of this invention to construct a multiple fuse which .ischaracterized by the ability to open a circuit of'high amperage withoutdamage to the fuse body, emission of flame, and without blowing any ofthe linksexcept the link in circuit. In order for alfuse: to pass theUnderwriters Laboratories short circuit test, it is necessary amongother things that it be capable of opening a circuit having a currentmagnitude of approximately 10,000 amperes. The are resulting fromopening a circuit of this type tends to blow all of the linkssimultaneously instead of the. one in circuit only and also tends todisrupt. the body of the fuse, or emit flame which constitutes firehazard.

The invention has for a still furtherobject the construction ofamultiple' fuse'which is characterized by a fume chamber for selectiveengagement overthe portion of each fuse link which blows to open thecircuit, and connected by unrestricted small passages with a second fumechamber having fume escape passages restricted to bleed off withrelation to said unrestricted passages. This arrangement is anexceptionally important. feature of the invention in that the fumes andflames build up a back pressure within the chambers whichcause theextinguishing of the flame.

As a further object of this invention it is proposed to constructamultiple fuse in which there is a core rotatively mounted and formedwith an interior fume chamber having the entrance port selectivelyengageable over fuse elements mounted within the fuse body, and in whichthe core has a peripheral groove fume chamber connected by openings tothe interior fume chamber in a manner so as to encase and choke theflame and gases formed by the blowing of one fuse, and further to allowthe gradual escape of the fumes through a tortuous path.

As a still further object of this invention it is proposed to arrange acap over said peripheral groove fume chamber and over a portion of thebody of the fuse in a manner so as to allow the gradual escape or bleedoff of the fumes as well as provide asecondary fume chamber wherein backpressure may build up and tend to extinguish the are as stated in theprevious paragraph.

Furthermore as another object of this invention it is proposed toarrange a fire resistant transparent or translucent material within thecap and beneath a portion provided with apertures denoting selectivelyeach of the fuse elements, and to provide an: arrangement to discolorthe fire. resist material selectively beneath each of the apertures asthe particular'fuse element denoted by'said aperture is blown. With thisarrangement the inspection of the fuse is suflicient to inform thenumber of good fuse elements and those blown.

Furthermore the invention also proposes the arrangement of the body andthe core of the fuse in a manner so as to have a plurality ofinterengaging shoulders with the fuseelements engagedv therebetweenandfollowing the contour between the body and coreand set-within groovesin one of these parts in a manner so as to form a tortuous passage forthefiames and" fumes and so force" the flames and fumes into theinterior fume chamber of the core.

Furthermore the invention contemplates the forming of the core of twosections: connected for unitary rotation by the provision of a finger onone of the sections engaging into an opening in the other of thesections, arid for the purpose of convenience inmolding the core andfurthermore. forv the provision of a construction in which one of thecore sections completely covers the end contact of the multiple fuse.

Furthermore it is proposed to arrange the opening in which thefinger'mentioned in the previous paragraph extends in such a manner thatthe opening is of greater size than the finger and forms the entrance tothe fume chamber within the interior of the core.

To increase the effective operation of the fuse the invention alsoproposes :an arrangement whereby each of the'fuse elements hasa reducedportion located in the vicinity of one of the shoulders between thebody-and the core and so arranged, that when the member fuse element isblown it will be blown at thereduced portion and so direct the flame andfumes through the entrance port ofthe core into the interior fumechamber.

Furthermore the invention contemplates arranging. each of the fuseelements in a manner so that the top endsare horizontaland .disposedupon a horizontal shoulder between the coreand the fuse body, andparticularly-within cavities formed insaid horizontal shoulder.

As a further object of-this invention'it :isproposed to arrange :ahorizontal contact spring adapted to selectively engage withinthe'cavities mentioned in the previous paragraphan'd connected with'aring in: sliding: contact toran extension of: the shell contact thusconcludlngtthe circuit from the central contact of the multiple fuse tothe shell contact.

The invention still further proposes an. arrangement whereby the lockconstruction is provided for holding the core against rotation andnecessitating the use of a key for turning the core to reset itsposition.

A still further object of this invention is the construction of amultiple fuse as mentioned which is simple and durable and that may bemanufactured and sold at a reasonable cost.

For further comprehension of the invention, and of the objects andadvantages thereof, reference will be had to the following descriptionand accompanying drawing, and to the appended claims in which thevarious novel features of the invention are more particularly set forth.

In the accompanying drawing forming a material part of this disclosure:

Fig. 1 is a plan view of a multiple fuse constructed according to thisinvention.

Fig. 2 is an enlarged sectional view taken on the line 22 of Fig. 1.

Fig. 3 is a horizontal sectional view taken on the line 3-3 of Fig. 2.

Fig. 4 is a fragmentary vertical detailed view taken on the line 4-4 ofFig. 2.

Fig. 5 is a fragmentary detailed view taken on the line 55 of Fig. 2.

Fig. 6 is a fragmentary horizontal sectional view taken on the line 6-6of Fig. 2.

Fig. '7 is a fragmentary view similar to a portion of Fig. 2 butillustrating a modified arrangement.

The multiple fuse according to this invention comprises a fuse body l0provided with a plurality of fuse elements I I. These fuse elements arearranged within grooves formed upon the interior face of the body, seeFig. 6. Each of the fuse elements is connected at its lower end, andthere connected with a central contact 12 in the form of a rivet engagedthrough the bottom of the fuse body. The rivet is punched at its innerend so as to securely hold its place. A small washer I3 is interposedbetween the punched end of the rivet and the junction of the fuseelements H to insure proper electrical connection. The exterior of thefuse body is provided with a customary shell contact M.

A core is rotative within and projects from the fuse body and iscomposed of an upper section l5 and a bottom section [6. This core isformed with an interior fume chamber [1, having an entrance port l8 atits bottom adapted to selectively engage over portions of the fuseelements II. The core is also provided with a second fume chamber shownspecifically to comprise a peripheral groove fume chamber l9 connectedwith unrestricted openings 20 to the interior fume chamber IT. Theunrestricted openings 25 preferably should be diametrically oppositeeach other and of substantially elliptical shape and slightly tapered asshown in-Fig. 2 tofacilitate the manufacture of the core. Since the coreis a moulded part the arrangement of the openings 20 allows the core. tobe withdrawn from the mould after the core is moulded.

Tofacilitate the rotating of the core it is provided at thetop with anoblong shaped handle 2|. The interior fume chamber I1 is so formedwithin the core that there is a thin upper flange 22'forming the topside of the peripheral groove fume chamber.

The cap 23 is engaged over the peripheral fuinechamber l9 and engagesover aportion of the body H]. To insure the proper holding of the capits bottom end 24 is bent over an exterior shoulder formed upon the bodyof the fuse. The plurality of longitudinal grooves 25 are arrangedwithin the periphery of a shoulder at the top of the fuse body so as toprovide a tortuous passage from the peripheral fume chamber E9 to theatmosphere. In other words fumes within the chamber l9 may escapethrough the restricted grooves 25 to the atmosphere.

An arrangement is provided whereby there is an indication as to thenumber of fuses blown. This arrangement comprises a sheet of fireresistant transparent or translucent material 26 arranged in fixedrelation with the cap 23 and particularly below the top of the cap. Thetop of the cap is formed with a number of apertures 2'5 numericallycorresponding with the number of fuse elements and arranged spaced fromeach other corresponding with the spacing of each of the fuse elementsH. The flange 22 is provided with a V-shaped opening 28 adapted toexpose a small area of the fire resistant material 26 to the groove fumechamber l9. It will readily be understood fumes and flame from the fumechamber 19 act against the small area of the fire resistant material 26which becomes blackened or darkened and this area will be viewablethrough one of the openings 21. As the core is rotated to a new positionthe V-shaped opening 28 correspondingly moves and so assumes a newlocation beneath a different one of the openings 21 and in this mannerthe area beneath the openings 2'! are selectively blackened as each ofthe fuse elements I l are blown. The arrow 29 upon the handle 2| of thecore indicates the particular position of the core in which one specificfuse element I I indicated by the aperture 21 in line with the arrow isin circuit between the contact shell and the central contact of thefuse.

A plurality of shoulders 3|], 3! and 32 are formed between the body ofthe fuseand its core. These shoulders are horizontal and are connectedwith each other by vertical portions or inclined portions. The fuseelements H are arranged in grooves in the fuse body and conformwith thecontour between the fuse body and the core. The plurality of shouldersform a tortuous path to prevent the fumes and flame passing up betweenthe fuse body and the core. Thus the fumes and flame take the path ofleast resistance which is through the entrance port l8 into the interiorfume chamber l1. Portions of each of the fuse elements II are reducedupon one of the shoulders or between certain of the shoulders, and asshown in Fig. 2, upon the inclined portion located between theshoulders. 39 and 3i. It is an object to so locate the reduced portions,one of said reduced portions is illustrated in Fig. 3 and indicated bynumeral N, that it is immediately below the entrance port l8 when theport is located over the member fuse element in the circuit. It will bereadily understood that when the fuse element is blown, it is at thereduced portion II which is electrically the high resistance point andso the resultant flame and gaseous fumes are immediately dischargedwithin the fume chamber I1.

As previously stated the core of the multiple fuse is formed from thesections [5 and IG.- The upper section I 5 is provided with a finger 33which extends downwards into a portion of the opening l8 and so connectsthe sections of the core for unitary rotation. The lower section of thecore l6 serves to cover the central contact l2 and also to cover all ofthe fuse elements ll except the one which is exposed through theentrance port. [8. Similarly the upper section l5 of the core serves tocover and enclose within their grooves, each of. the upper portions ofthe fuse elements I l The extreme upward ends of each of the fuseelements II are disposed horizontally and extend across the bottom ofcavities 34 formed in the upper shoulder 32 in the fuse body. Theseportions of each of the fuse elements II are exposed. Each of thecavities 34 connects with a circular groove 35 in the top shoulder 32and in the fuse body. This circular groove 30 is for the purpose ofaccommodating the contact finger 35 adapted to selectively make contactwith each of the upper ends of the fuse elements II. More particularlythe contact finger 36 is in electrical connection with the contact ring31 secured upon the shoulder 32 of the core of the fuse. This contactring 31 not only extends across the groove 35, but also extends over theupper end of a connection 38 which is in electrical connection with thecontact shell l4. Thus in all positions of rotation of the core therewill be an electrical connection between the contact shell I4 and thering 31. From the ring 31 the current may continue to the contact finger36, which in practice preferably should be integral with the ring 31 asclearly shown in Fig. 5, and hence to one of the fuse elements lldepending upon which of the cavities 34 the contact finger 36 engagesin.

Inspecting Fig. 6 it should be noticed that the core is in contact withthe inner face of the fuse body and so closes possible passage of flamesand fumes between the grooves in which the fuse elements H aredisplaced. Furthermore it should be borne in mind that the fireresistant material 25 is stationarily secured within the cap 23 which inturn is also stationary relative to the fuse body. It is necessary thatthe fire resistant material 26 and the cap 23 be stationary so that theV-shaped opening 28 properly aligns with the openings 2! to blacken thefire resistant material 26 and indicate which of the fuse elements areblown. The electric circuit may be traced from the central contact l2through each of the fuse elements H. The circuit then continues from oneof the fuse elements to the contact finger 36, the ring 31, theconnection element 38 to the contact shell [4. When the particular fuseelement I l blows the flame and fumes fill the fume chamber I! and thenpass through the openings to the peripheral groove fume chamber I9 andfrom there through the passages to the atmosphere. Particular attentionis called in the fact that as the flame and fumes fill the fume chamber11 they cause the air to back up through the unrestricted passages 20into the second fume chamber l9 and the atmosphere under therestrictions of the passages and thus create a back pressure which serveto extinguish the flame. Then the fumes may escape through therestricted passages 25. The construction of the double fume chamber withthe restrictions to create the back pressure is a very important part ofthe invention since it prevents the flame from reaching the exterior ofthe fuse plug which would be a fire hazard. The sum total of thepassages 25 should be materially smaller, in other words, restricted,relative to the sum total of the passages 20 for helping and creatingthe back pressure.

In Fig. '7 a modification of the invention has been disclosed in which akey is necessary to rotate the core for resetting the fuse from onecondition. In detail, a plurality of tumblers 4!] are arranged inopenings extending from the core section l5 into a protuberance 4|connected with the cap 23'. A key 42 is adapted to engage within a keyopening in the top of the core and move the tumblers 40 into positionsin which the core is free to rotate. The drawing shows only one group oftumblers for locking the core in one position only corresponding withone fuse.

Further detailsof the lock construction will not be given here sinceanyone skilled in the art would understand its construction from thebrief explanation. Thus unauthorized persons cannot turn the core forresetting the multiple fuse.

While I have illustrated and described my invention with some degree ofparticularity, I realize that in practice various alterations thereinmay be made. I therefore reserve the right and privilege of changing theform of the details of construction or otherwise altering thearrangement of the correlated parts without departing from the spirit orthe scope of the appended claims.

Having thus described my invention, what I claim as new, and desire tosecure by United States Letters Patent is:

1. In a multiple fuse, a body with a plurality of fuse elements, a corerotative within said body and formed with an interior fume chamberhaving an entrance port selectively engageable over said fuse elements,said core having a peripheral groove fume chamber connecting withrestricted discharge passages to the atmosphere and connected withunrestricted openings to said interior fume chamber, and a cap engagingover said peripheral groove fume chamber and a portion of said body.

2. In a multiple fuse, a body with a plurality of fuse elements, a corerotative within said body and formed with an interior fume chamberhaving an entrance port selectively engageable over said fuse elements,and means for visually indicating the blowing of each fuse element.

3. In a multiple fuse, a body with a plurality of fuse elements, a corerotative within said body and formed with an interior fume chamberhaving an entrance port selectively engageable over said fuse elements,said core having a peripheral groove fume chamber connected withopenings to said interior fume chamber, a cap engaging over saidperipheral groove fume chamber and a portion of said body and adapted toallow the gradual escape of fumes to the atmosphere, and means forvisually indicating the blowing of each fuse element, comprising fireresistant material within said cap and stationarily connected therewithand transparent or translucent in nature and located beneath aperturesformed in said cap corresponding selectively with said fu'se elements,and said core being formed with an opening connecting said peripheralfume groove chamber with an area of said fire resistant material locatedbeneath one of the openings in said cap.

4. In a multiple fuse, a body with a plurality of fuse elements, a corerotative within said body and formed with an interior fume chamberhaving an entrance port selectively engageable over portions of saidfuse elements, and said body and core having interengaging shoulders,said fuse elements following the contour between said core and body andbeing located in grooves in one of said members, each fuse elementhaving a reduced portion adapted to direct at the proper time the flamesand fumes into said entrance port, said core being composed of an upperand a lower section connected. for unitary rotation, with the provisionof a finger from one of the sections engaging in an opening in the othersection, said latter mentioned opening comprising said entrance port.

5. In a, multiple fuse, a body with a plurality of fuse elements, a corerotative within said body and formed with an interior fume chamberhaving an entrance port selectively engageable over portions of saidfuse elements, and said body and core having interengaging shoulders,said fuse elements following the contour between said core and body andbeing located in grooves in one of said members, each fuse elementhaving a reduced portion adapted to direct at the proper time flames andfumes into said entrance port, the upper ends of each of the fuseelements being extended horizontally beneath one of the shouldersbetween said body and core and within cavities in said shoulder, and acontact spring upon the core selectively engageable within said.cavities to make electrical contact with said fuse element.

6. In a multiple fuse, a body with a plurality of fuse elements, a corerotative within said body and formed with an interior fume chamberhaving an entrance port selectively engageable over portions of saidfuse elements, and said body and core having interengaging shoulders,said fuse elements following the contour between said core and body andbeing located in grooves in one of said members, each fuse elementhaving a reduced portion adapted to direct at the proper time flames andfumes into said entrance port, the upper ends of each of the fuseelements being extended horizontally beneath one of the shouldersbetween said body and core and within cavities in said shoulder, and acontact spring upon the core selectively engageable within said cavitiesto make electrical contact with said fuse element, said horizontalcontact finger being connected with a contact ring secured upon thelatter mentioned shoulder of said core and in electrical contact with amember extended through the fuse body and connected with the contactshell of said fuse.

7. In a multiple fuse, a body with a plurality of fuse elements, a corerotative within said body and formed with an interior fume chamberhaving an entrance port selectively engageable over portions of saidfuse elements, and said body and core having interengaging shoulders,said fuse elements following the contour between said core and body andbeing located in grooves in one of said members, each fuse elementhaving a reduced portion adapted to direct at the proper time flames andfumes into said entrance port, the upper ends of each of the fuseelements extended horizontally beneath one of the shoulders between saidbody and core and within cavities in said shoulder, and a contact springupon the core selectively engageable within said cavities to makeelectrical contact with said fuse element, said horizontal contactfinger being connected with a contact ring secured upon the lattermentioned shoulder of said core and in electrical contact with a memberextended through the fuse body and connected with the contact shell ofsaid fuse, said horizontal contact finger being integral with saidcontact ring.

8. In a multiple fuse, a fuse body, a core rotative therein for changingthe connection through the various fuse elements of said multiple fuse,and a lock interposed between said core and a stationary part of saidfuse body for holding said core against rotation.

9. In a multiple fuse, a fuse body, a core rotative therein for changingthe connection through the various fuse elements of said multiple fuse,and a lock interposed. between said core anda stationary part of saidfuse numerally for holding said core against rotation, said lockcomprising a plurality of spring urged tumblers between said core andsaid stationary element, and a key opening adapted to receive a keycapable of moving said tumblers into their open positions.

10. In an article of the class described having a plurality of fuselinks, an interior fume chamber selectively engageable over the portionof each of the fuse links which blows to open the circuit, and a secondfume chamber joined with said interior fume chamber with unrestrictedpassages and itself having fume escape passages restricted relative tosaid unrestricted passages.

11. In a multiple fuse,'an interior fume chamber selectively engageableover the portion of each fuse link which blows to open the circuit, anda second fume chamber joined with unrestricted passages with saidinterior fume chamber, said second fume chamber having fume escaperestricted passages.

12. In a multiple fuse, an interior fume chamber with a small entranceport selectively engageable over the portion of each fuse link whichblows to open the circuit, a second fume chamber, joined with saidinterior fume chamber'with unrestricted passages and itself having fumeescape passages restricted relative to said unrestricted passages.

13. Ina multiple fuse, a rotative core formed with an interior fumechamber selectively engageable over the fuse elements, and said corehaving a second fume chamber joined with unrestricted passages with saidinterior fume chamber, said second fume chamber having fume escapepassages restricted with relation to said unrestricted passages.

14. In a multiple fuse, a rotative core formed with an interior fumechamber selectively engageable over the fuse elements, and said corehaving a second fume chamber joined with unrestricted passages with saidinterior fume chamber, said second fume chamber having fume escapepassages restricted with relation to said unrestricted passages, saidinterior fume chamber being longitudinal within the core, and saidsecond fume chamber being peripheral around said core.

SAMUEL JOSEPH WYNN.

